1. Field of the Invention
This invention relates to apparatus for use in disc players and, more particularly, to novel and highly-effective disc loading and unloading apparatus for automatically engaging a disc that has been inserted into a disc player through an opening for disc insertion and for selectively loading the disc on a disc rotating device provided in the disc player and unloading the disc from the disc rotating device.
2. Description of the Prior Art
Several forms of disc loading and unloading apparatus have been proposed for loading a disc that is used for recording or reproduction of an information signal on a disc rotating device provided in a disc player and unloading the disc from the disc rotating device. One such disc loading and unloading apparatus, which has been proposed for miniaturizing the disc player, has a loading arm supported on a stationary structure so as to be rotatable, a drive roller mounted on the loading arm and caused to rotate, and an idler roller attached to the stationary structure and positioned above the drive roller.
In the disc loading operation of such a disc loading and unloading apparatus, the loading arm is so positioned that the drive roller engages the idler roller and is driven in rotation thereby, and a disc is received between the drive roller and the idler roller and carried to a position above the disc rotating device by rotation of the drive roller. Then the loading arm is rotated to cause the drive roller to descend, so that the disc, which rests on the drive roller, also descends and engages the disc rotating device. Afterwards, the loading arm is further rotated to cause the drive roller to descend farther so as to be spaced apart from the disc on the disc rotating device. In this manner, the disc is automatically loaded on the disc rotating device.
In the disc unloading operation of the disc loading and unloading apparatus described above, the loading arm is rotated to cause the drive roller to ascend to remove the disc from the disc rotating device. The disc removed from the disc rotating device ascends together with the drive roller and is received between the drive roller and the idler roller. Then the drive roller is caused to rotate in the direction opposite to the direction of rotation in the disc loading operation, so that the disc is carried toward the opening for disc insertion by the drive roller and the idler roller rotating together. After the rotation of the drive roller is completed, the disc is held at the opening for disc insertion with a portion thereof protruding through the opening. If the disc is not accompanied by a protective disc case, the portion of the disc protruding through the opening is exposed to the outside of the disc player. If a disc case is engaged in the opening, the portion of the disc protruding through the opening is received within the disc case. In either case, the disc is automatically unloaded from the disc rotating device and can be easily withdrawn from the disc player.
If the disc is not accompanied by the disc case and is continuously held at the opening for disc insertion with a portion thereof exposed through the opening to the outside of the disc player for a relatively long time after being unloaded, the portion of the disc exposed to the outside of the disc player becomes covered with dust and is likely to be damaged by something colliding therewith. As a result, signal reproduction from the disc cannot be performed properly.
An improved disc loading and unloading apparatus that avoids such an undesirable situation as mentioned above in connection with the disc without the disc case has been proposed by the assignee of the present application in Japanese patent application No. 59/172794, filed Aug. 20, 1984. This improved disc loading and unloading apparatus has a loading and unloading mechanism for performing selectively a disc loading operation in which a disc inserted into a disc player through an opening for disc insertion is loaded on a disc rotating device provided in the disc player and a disc unloading operation in which the disc is removed from the disc rotating device, carried to the opening for disc insertion, and then held at the opening with a portion thereof exposed through the opening to the outside of the disc player. Drive control means is provided for controlling the loading and unloading mechanism to commence automatically the disc loading operation when it is detected that the disc has been continuously held at the opening for disc insertion with a portion thereof exposed to the outside of the disc player for a predetermined duration after being unloaded. In the operation of such an improved disc loading and unloading apparatus, when the disc has been continuously held at the opening for disc insertion with a portion thereof exposed to the outside of the disc player for the predetermined duration after the disc unloading operation, it is automatically loaded again on the disc rotating device, so as to be prevented from continuing indefinitely to be held at the opening with a portion thereof exposed to the outside of the disc player.
However, in the disc player employing the improved disc loading and unloading apparatus mentioned above, there is an inconvenience arising with use of a disc accompanied by a disc case. A disc accompanied by a disc case is contained in the disc case when it is not in use. When the disc is in use, the disc case is engaged within the opening for disc insertion and the disc is drawn out of the disc case by a disc handling device provided in the disc player. The disc withdrawn from the disc case undergoes the same disc loading and unloading operations as a disc used without a disc case, and is then reinserted into the disc case after the disc unloading operation. Accordingly, even if the disc is continuously held at the opening for disc insertion for a relatively long time after being unloaded, there is no risk of the disc becoming covered with dust or of the disc being damaged by objects colliding therewith. This means that it is not necessary to load the disc again on the disc rotating device when the disc has been continuously held at the opening for disc insertion for the predetermined duration after being unloaded. If the disc loading operation is uselessly performed for automatically loading the disc again on the disc rotating device when the disc has been continuously held at the opening for disc insertion for the predetermined duration after being unloaded, an extra disc unloading operation must be carried out when a user of the disc player wishes to remove the disc therefrom. This necessitates undesirable waiting time.